1. Field of the Invention
The invention relates to a surgical apparatus and method for performing anastomosis.
2. Background
Anastomosis is a procedure by which two hollow tissue structures are joined together. More particularly, vascular anastomosis is a procedure by which two blood vessels within a patient are surgically joined together. Vascular anastomosis is performed during treatment of a variety of conditions including coronary artery disease, diseases of the great and peripheral vessels, organ transplantation, and trauma. In coronary artery disease (CAD), for example, an occlusion or stenosis in a coronary artery interferes with blood flow to the heart muscle. Treatment of CAD sometimes involves attaching a graft, in the form of a prosthesis or harvested artery or vein, to one or more of the coronary arteries to reroute blood flow around the occlusion and restore adequate blood flow to the heart muscle. This treatment is known as coronary artery bypass grafting (CABG).
In a conventional CABG procedure, a large incision is made in the chest, and the sternum is sawed in half to allow access to the heart. In addition, a heart-lung machine is used to circulate the patient's blood so that the heart can be stopped and the anastomosis can be performed. In order to minimize the trauma to the patient induced by conventional CABG, less invasive techniques have been developed in which the surgery is performed through small incisions in the patient's chest with the aid of visualizing scopes. In both conventional and less invasive CABG procedures, the surgeon has to suture one end of the graft vessel to the coronary artery and the other end of the graft vessel to a blood-supplying artery, such as the aorta. The suturing process is a time consuming and difficult procedure requiring a high level of surgical skill. In order to perform the suturing of the graft to a target vessel, such as the coronary artery, a surgeon holds the edges of the incision in the target vessel with one hand and holds a needle in the other hand for suturing, or an assistant may hold the edges of the incision in the target vessel while a surgeon makes small stitches as close as possible to the edges of the incision. In addition, during conventional CABG procedures, blood flow at the anastomosis site is stopped during suturing. This prevents bleeding from the incision site but also prevents blood from reaching a portion of the heart muscle served by the vessel. Further, during off-pump CABG procedures a side clamp or other device may be used to isolate a portion of the wall of the aorta to which a graft vessel is sutured. The use of a side clamp or similar device can cause emboli to detach from the wall of the aorta and enter the bloodstream, which is undesirable.
To address these challenges, surgical stapling devices and method have been developed for use in CABG procedures. The assignee of the present application, for example, has developed a number of such devices and methods, such as those described, for example, in U.S. Pat. No. 7,682,368, which is hereby incorporated by reference in its entirety.
In another example of an anastomosis procedure, a graft may also be placed on an aorta for a number of different reasons. In CABG procedures, the blood pressures and blood flows encountered in coronary arteries are typically both quite low, due to the occluded state of the coronary arteries being operated on. Also, coronary arteries are relatively small-diameter blood vessels. In contrast, blood pressure and blood flow in the aorta are typically quite high, and the aorta is much larger than the coronary arteries. Due at least in part to the high pressures and flows encountered in the aorta, surgical staples have not been used previously in anastomosis procedures involving the aorta.
The use of the same reference symbols in different figures indicates similar or identical items.